Inflatable air bags for the protection of vehicle occupants are well known. Typically the passenger side air bag is hidden inside the instrument panel, concealed by an air bag cover. Inflation of the air bag occurs with great force and the air bag usually exits the instrument panel by impacting the cover and forcing it outward, potentially in the direction of the occupants. The consequences of this impact are twofold: first, deployment of the air bag can be inhibited, and second, the air bag cover can detach or break apart, often hurtling the cover or pieces of it toward the occupants.
U.S. Pat. No. 5,460,401, issued on Oct. 24, 1995 to Gans et al., describes a method to address the potential injury to occupants by providing an air bag cover that is limited in its movement by the presence of a flexible tether. One end of the tether attaches to the cover, the other end attaches to the panel edge or housing. Although the tether reduces the risk to occupants by restricting the outward motion of the cover, the cover is still thrust outward with great force and the potential for injuriously impacting the occupants has not been eliminated.
U.S. Pat. No. 5,456,487, issued on Oct. 10, 1995 to Daris et al., describes an instrument panel assembly that provides an air bag cover that consists of two hinged doors within the instrument panel. Both of the doors are designed to swing outwardly as the air bag is deployed. Although the outward movement of the doors is again restricted, the doors are still thrust outward with great force and body parts in close proximity to the doors—e.g., hands and wrists-could still be injuriously impacted.
U.S. Pat. No. 5,915,724, issued on Jun. 29, 1999 to Daris, et al., describes an air bag cover assembly that provides an air bag cover with a single hinged door. The '724 patent provides a device that has the same limitations as that provided by the '487 patent. Although manufactured differently than a two-door hinged cover, the single-door cover still presents the same risk to the occupants as the two-door design.
U.S. Pat. No. 5,971,431, issued on Oct. 26, 1999 to Wohllebe, et al., describes an air bag arrangement that provides a cover with a guide to direct movement of the cover. Upon deployment of the air bag, the air bag impacts the guide and a downward force component moves the cover to reveal an opening. The movement of the cover is limited by swing levers that restrain the cover from moving toward the occupant. This eliminates the problem of the cover propelling toward the occupant; however, the cover does not move until the guide is impacted by the air bag, and this could potentially inhibit the air bag deployment.
U.S. Pat. No. 6,024,377, issued on Feb. 15, 2000 to Lane, Jr., describes an air bag restraint system, one embodiment of which provides a jaw-like air bag cover with side rails. Upon inflation of the air bag, a shaft is forced into the intersection of the side rails, causing a camming action which opens the jaws. Once open, the air bag deploys through the opening in the jaws. This design has the same shortcoming as the '431 patent; although the cover is not propelled in the direction of the occupant, the air bag must forcibly open the cover, and this could potentially inhibit the air bag deployment.
Another embodiment of the '377 patent overcomes the potential problem of inhibiting deployment of the air bag, but introduces the problem of a cover moving toward the occupant. This embodiment provides an air bag concealed within a sliding drawer. Upon receipt of a signal from a controller, gas is used both to inflate the air bag, and to propel the drawer forward which allows the air bag to deploy through an opening at the top of the drawer. The system may have separate inflators—that is, one for the air bag and one to force the drawer open—in which case they may work concurrently or sequentially, or a single inflator can serve both functions. Because the drawer is sliding toward the occupant, potentially with great force, the risk of injury to the occupant remains.
Accordingly, it is desirable to provide an improved system of allowing an air bag to deploy which overcomes the above referenced shortcomings of prior art air bag deployment systems. Specifically, it is desirable to provide a system of allowing an air bag to deploy without obstruction, such that the air bag need not impact the air bag cover, and therefore deployment is not inhibited. This eliminates the potential for occupant injuries caused by the propulsion of the cover or pieces thereof.